Ultraviolet irradiation can be used as an adjuvant therapy for onychomycosis, but it needs to be combined with antifungal medications. Its effectiveness is limited in severe cases, and attention should be paid to proper operation and individual differences. The wavelengths commonly used for adjuvant treatment of onychomycosis are 253.7 nm (UVC band) or 222 nm (far-UVC), but their applicability should be comprehensively evaluated based on irradiation dose, device type, and the patient’s individual condition.

1. UVC Wave Band (200–280 nm)

Sterilization Mechanism: Destroys the DNA/RNA structure of microorganisms, preventing their replication and proliferation.

Key Wavelengths:

253.7 nm: The main wavelength of traditional UV sterilization lamps, highly effective against bacteria, viruses, and some fungi.

222 nm: Far-UVC, with weaker penetration, but can penetrate the nail surface to kill fungi while minimizing damage to skin and eyes.

2. UVB Wave Band (280–320 nm)

Has certain lethality against dermatophytes (e.g., Trichophyton rubrum), but sterilization effect is weaker than UVC, usually requiring higher doses or combination with other treatments.

3. UVA Wave Band (320–400 nm)

Has strong penetration but weak sterilization effect, generally not used alone for treating onychomycosis.

 （222nm UV Germicidal Lamp）

Mechanism of Action

The adjunctive effect of ultraviolet (UV) irradiation in treating onychomycosis (nail fungus) is primarily based on its antimicrobial and anti-inflammatory properties:

Antimicrobial Effect: UV light can damage the DNA structure within fungal cells, causing DNA strand breaks and rendering the fungi inactive. This action inhibits fungal growth and reproduction, helping to control the progression of onychomycosis.

Anti-inflammatory Effect: UV irradiation can also suppress immune responses and reduce the production of inflammatory mediators, thereby exerting an anti-inflammatory effect. This helps alleviate local tissue swelling and itching caused by nail fungus, improving patient comfort.

Effectiveness Analysis

The therapeutic effect of ultraviolet (UV) irradiation on onychomycosis varies depending on the severity of the condition:

Mild Onychomycosis: In cases of mild nail fungus, UV irradiation may provide certain adjunctive benefits. It can help control fungal growth and promote local blood circulation, thereby improving the appearance and texture of the nails.

Severe Onychomycosis: For more severe cases, the effectiveness of UV irradiation may be limited. These cases generally require a more comprehensive treatment approach, including oral antifungal medications, topical agents, or laser therapy.

Precautions

When using ultraviolet irradiation for the treatment of onychomycosis, the following points should be noted:

Dose Control: The UV dose must be strictly controlled to avoid damage to healthy skin tissue. Excessive UV exposure may cause adverse reactions such as redness, pain, or blisters.

Personal Protection: During UV treatment, protective measures such as safety goggles and disposable gloves should be worn to minimize UV exposure to the eyes and skin.

Individual Differences: Patients may vary in their absorption and response to UV light. Some individuals may be less sensitive to UV, resulting in limited therapeutic effect.

Combination Therapy: UV irradiation is generally used as an adjunctive treatment for onychomycosis and should be combined with other therapies (e.g., antifungal medications) to improve overall effectiveness.